Hydrocarbonaceous black oil conversion process

ABSTRACT

Asphaltene-containing hydrocarbonaceous black oils are subjected to conversion conditions in a two-stage process. The physical characteristics of the catalytic composite disposed within the individual stages, or reaction zones, are different. This difference in physical characteristics is directed toward macropore volume, and is maintained whether the chemical composition is the same, or varies.

United States Patent 0 Hara 1 Feb. 8, 1972 [54] HYDROCARBONACEOUS BLACK OIL CONVERSION PROCESS [72] Inventor: Mark J. OHara, Prospect Heights, 111.

[73] Assignee: Universal Oil Products Company, Des

Plaines, Ill.

[22] Filed: May 13, 1970 21 Appl. No.: 37,023

[52] US. Cl ..208/59, 208/111, 208/112,

3,161,585 12/1964 Gleim et a1. ..208/264 3,216,953 1 1/1965 Krempff ..252/477 3,231,488 1/1966 Gatsis et a1. ...208/264 3 ,467,602 9/ 1 969 Koester ...252/477 3,558,474 1/1971 Gleim et a1. ..208/108 Primary Examiner-Delbert E. Gantz Assistant Examiner-G. E. Schmitkons Attorney-James R. Hoatson, Jr. and Robert W. Erickson [57] ABSTRACT Asphaltene-containing hydrocarbonaceous black oils are subjected to conversion conditions in a two-stage process. The physical characteristics of the catalytic composite disposed within the individual stages, or reaction zones, are different. This difference in physical characteristics is directed toward macropore volume, and is maintained whether the chemical composition is the same, or varies.

7 Claims, N0 Drawings IIYDROCARBONACEOUS BLACK OIL CONVERSION PROCESS APPLICABILITY OF INVENTION and nitrogenous compounds.

Petroleum crude oils, and topped or reduced crude oils, as

.well a other heavy hydrocarbon fractions and or distillates, in-

cluding heavy cycle stocks, visbreaker liquid effluent, atmospheric and vacuum crude tower bottoms products, shale oils, coal tars, tar sand oils, etc., all of which are commonly referred to in the art as black oils, are contaminated by significant quantities of various nonmetallic and metallic impurities. Among the nonmetallic contaminants are nitrogen, sulfur and oxygen. In addition, heavy hydrocarbonaceous black oil contains high molecular weight asphaltenic compounds. These are nondistillable coke precursors which generally contain sulfur, hydrogen, oxygen and various metallic components. Of the metallic contaminants, those comprising nickel and vanadium are most common, generally existing as organometallic compounds of relatively high molecular weight. With respect to a process for effecting the conversion of such hydrocarbon fractions, the presence of asphaltenic material interferes considerably with the capability of the catalytic composite to effect the destructive removal of nitrogenous, sulfurous and oxygenated compounds, as well as its ability to convert heavy hydrocarbonaceous material into lower-boiling products.

A wide variety of heavy hydrocarbon fractions and or distillates may be converted and substantially decontaminated through the utilization of the present invention. Exemplary of such charge stocks is a Wyoming sour crude oil having a gravity of 232 A.P.I. at 60 F., contaminated by 2.8 percent by weight of sulfur, 2,700 ppm. of total nitrogen, and containing a high-boiling pentane-insoluble asphaltenic fraction in an amount of about 8.4 percent by weight. Another such charge stock is a crude tower bottoms product, having a gravity, or 14.3 A.P.I., and containing 3.0 percent by weight of sulfur, 3,830 ppm. of total nitrogen, 85 ppm. of total metals and about 10.93 percent by weight of asphaltenic compounds.

In accordance with the present invention, such hydrocarbonaceous charge stocks are processed in a fixed-bed catalytic system containing at least two physically different catalytic composites. As hereinafter set forth in greater detail, the emphasis is on the physical differences of the catalytic composites rather than the chemical characteristics. That is, the composition of the catalytic composites may be the same, or may be different, the important criteria being the physical differences between the two catalytic composites.

OBJECTS AND EMBODIMENTS A principal object of the present invention is to provide a process for the conversion of an asphaltene-containing hydrocarbonaceous charge stock. A corollary objective is to effect a substantial degree of decontamination with respect to sulfurous and nitrogenous compounds.

Another object of the present invention is to afford a twostage process wherein insoluble asphaltene conversion is effected in the first stage with hydrocracking and additional asphaltene-conversion being effected in the second stage.

As hereinabove set forth, these objectives are achieved through the utilization of catalytic composites having different physical characteristics. Therefore, in one embodiment, the present invention provides a process for the conversion of an asphaltene-containing hydrocarbonaceous charge stock which comprises reacting said charge stock and hydrogen in a first reaction zone, in contact with a first catalytic composite, more than 50.0 percent of the macropore volume of which is characterized by pores having pore diameters greater than about 1,000 angstroms, and reacting the resulting first zone effluent and hydrogen in a second reaction zone, in contact with a second catalytic composite, less than 50.0 percent of the macropore volume of which is characterized by pores having pore diameters greater than 1,000 angstroms.

Other embodiments of my invention involve operating conditions and techniques, as well as preferred catalytic components for use in the multiple reaction zones. Addiu'onal embodiments involve the means through which the different physical characteristics are derived. As hereinafter set forth, one such means involves the concentration of boron phosphate within the porous carrier material with which the catalytically active metallic components are combined.

SUMMARY OF THE INVENTION As essential feature of the present invention involves the utilization of catalytic composites having different physical properties. It is understood that these catalytic composites may be disposed in individual, separate reaction zones in series flow, or in a single reaction zone in piggy-back fashion. It is further understood that the particular selection of catalytically active metallic components is not essential, and that the two catalytic composites may have the same, or different chemical composition. In the art of catalysis, the physical properties of a catalytic composite are considered to be the apparent bulk density, the surface area, the pore volume and the average pore diameter. With respect to the pore volume of the catalytic composite, the art considers the macropore volume (MPV) thereof to consist of those pores having pore diameters in the range of 117 to 58,000 angstroms. The present invention is founded upon recognition of the fact that a catalytic composite, more than 50.0 percent of the macropore volume of which is characterized by pores having pore diameters greater than about 1,000 angstroms is highly efiicient for the conversion of insoluble asphaltenes, notwithstanding its relatively low degree of hydrocracking activity. Conversely, a catalytic composite, less than 50.0 percent of the macropore volume of which is characterized by pores having pore diameters greater than 1,000 angstroms is very effective as a hydrocracking catalyst, but ineffective with respect to the conversion of the insoluble asphaltenes.

The catalytic composites, for utilization in the present process, comprise metals selected from Groups VI-B and VIII of the Periodic Table combined with a porous carrier material. Metals from Group VI-B and VIII are intended to include those indicated in the Periodic Table of the Elements, EH. Sargent & Company, 1964. Thus, the catalytic composite may comprise one or more metallic components from the group of molybdenum, tungsten, chromium, iron, cobalt, nickel, platinum, palladium, iridium, osmium, rhodium, ruthenium and mixtures thereof. In view of the expense involved with the noble metals of Group VIII, the preferred Group VIII metals are iron, cobalt and nickel. The porous carrier material may comprise alumina, silica, zirconia, magnesia, titania boria, strontia, hafnia, and mixtures of two or more including silicaalumina, silica-zirconia, silica-magnesia, silica-titania, alumina-zirconia, alumina-magnesia, silica-titania, alumina-zirconia, alumina-magnesia, alumina-titania, magnesia-zirconia, titania-zirconia, silica-alumina-zirconia, etc. It is preferred to utilize a porous carrier material containing at least a portion of silica and preferably a composite of alumina and silica containing from about 10.0 percent to about 90.0 percent by weight of silica.

Although neither the composition, nor the method of preparing the catalytic composite is essential to my invention, certain criteria are observed and are generally preferred. For example, that catalytic composite wherein more than 50.0 percent of the macropore volume is characterized by pores having pore diameters greater than about 1,000 angstroms, will generally have an apparent bulk density below about 0.40, and generally in the range of from about 0.25 to about 0.40 (grams per cc.). Conversely, the catalytic composite wherein less than 50.0 percent of the macro pore volume is characterized by pores having pore diameters greater than 1,000 angstroms, generally has an apparent bulk density in the range of about 0.4 to about 1.0. One method of effecting the variance in the macropore volume characteristics is through the utilization of boron phosphate as a component of the porous carrier material. Where the porous carrier material contains from about 5.0 percent to about 30.0 percent by weight of boron phosphate, the macropore volume is characterized in that more than 50.0 percent consists of pores having pore diameters greater than about 1,000 Angstroms. Where the porous carrier material contains less than 5.0 percent by weight of boron phosphate, or none at all, the macropore volume is characterized in that less than 50.0 percent contains pores having pore diameters greater than 1,000 angstroms. Similarly, the macropore volume characteristics are afi'ected by the temperat$re employed in oxidizing the final catalytic composite. This oxidation treatment, effected at elevated temperature, is considered to be the final step in the manufacturing technique designed to produce a finished catalyst. Such oxidation treatment is generally carried out in an atmosphere of air at a temperature in the range of about 800 F. to about l,400 F. (427 to 760 Q). My investigations have indicated that the oxidation temperature has an etfect on the physical properties of the catalytic composite. Thus, where the catalyst is oxidized at a temperature above about 600 C., and preferably in the range of about 610 to about 650 C., large pores will develop and the macropore volume will be characterized in that 50.0 percent thereof will have pores with pore diameters greater than about 1,000 angstroms. At temperatures below about 600 C. and preferably in the range of about 550 C. to about 600 C. the less porous composite is obtained.

With respect to the catalytically active metallic components, preferred catalysts contain at least one metallic component from Groups Vl-B and VH1. The Group Vl-B components, molybdenum, tungsten, or chromium, are utilized in an amount of about 4.0 percent to about 30.0 percent by weight, with molybdenum and or tungsten being particularly preferred. The Group Vlll metallic components will be employed in amounts within the range of about 1.0 percent to about 10.0 percent by weight, and, as hereinbefore set forth, the iron-group metals, iron, cobalt, and nickel, are generally preferred.

EXAMPLE This example is presented for the purpose of illustrating further my invention as hereinbefore set forth. Catalyst A, the highly porous catalyst, was prepared by initially blending aluminum sulfate and acidified water glass in amounts to yield 88.0 percent by weight alumina. The precipitation was effected through the addition of the blend to ammonium hydroxide, with all precipitation taking place at a pH above 8.0. The gel, or precipitate, was washed free of sulfate and sodium ions in a catalyst washing tower, and subsequently reslurried in hot water. A boric acid-phosphoric acid solution, in a mol ratio of 1:1, was added in an amount which resulted in a solids content of about 68.0 percent alumina, 10.0 percent silica and 22.0 percent boron phosphate on a weight basis. The gel was then dried at a temperature in the range of 200 to 400 F., and ground to a size approximating 10-30 mesh. 1mpregnation of this granular carrier material was effected through the use of an aqueous solution of nickel nitrate hexahydrate and molybdic acid (about 80.0 percent M 0 in sufficient quantities to result in a finished catalyst containing 2.0 percent by weight of nickel and 16.0 percent by weight of molybdenum, calculated as the elemental metals. The impregnated material was dried and calcined, in an air atmosphere, for 1 hour at a temperature of about 600 C. Analyses indicated that the finished catalyst had an apparent bulk density of about 0.32 grams/cc, a surface area of 215 square meters per gram, a pore volume of 0.49 cc./gram and an average pore diameter of about 91 angstroms. The total macropore volume, 1.1245 cc./gram, was determined by mercury porosimeter analysis. The following Table 1 illustrates the distribution of pores, of varying diameter, in the macropore volume range of 1 17 to 58,000 angstroms.

TABLE I MPV Characteristics, Catalyst A Pore diameter range, A. MPV, percent of total From the foregoing table, it will be ascertained that this catalyst has 62.5 percent of its macropore volume characterized by pores with pore diameters greater than about 1,000

Catalyst B was prepared by impregnating spherical (1/16- inch) silica-alumina particles, 60.0 percent by weight of silica, with an aqueous solution of nickel nitrate hexahydrate and tungstic acid. The finished catalyst, after drying and calcination at about 600 C., indicated 1.6 percent nickel and 13.5 percent tungsten on an elemental weight basis.

Analyses of catalyst B further indicated an apparent bulk density of about 0.77 grams/co, a surface area of 289 square meters per gram, a pore volume of 0.60 cc./gram and an average pore diameter of 83 angstroms. The total macropore volume was 0.1073, and the distribution of pores, by pore diameter, in the macropore volume range, was found to be that shown in the following Table I]:

TABLE [1 MPV Characteristics, Catalyst B Pore diameter range A. MPV, percent of total This catalyst has 97.0 percent of its macropore volume characterized by pores having pore diameters less than 1,000 angstroms.

CATALYST TEST PROCEDURE The Relative Activity (RA) test procedure is based upon the conversion of heptane-insoluble asphaltenes contained in a 950 F .-plus vacuum tower bottoms product having a 27.0 I

A total of 150 cc. of catalyst is employed, and a quartz chip preheat section is used above the first layer. The reactor is pressured to 3,000 p.s.i.g., with a circulating stream of hydrogen, and the catalyst inlet temperature slowly raised to a level of 300 C. While maintaining this temperature, the hydrogen recycle rate is established at about l5,000 scfJBbl. and the charge stock is introduced. After about 300 grams of charge stock have passed through the catalyst beds, the inlet temperature of the catalyst is raised to 380 C.

Following a 27-hour lineout period, two test periods, of 4 hours duration each, are effected at the higher temperature and at varying liquid hourly space velocities of 0.5 and 1.0, all other conditions being maintained constant. The results of the two test periods are plotted on semilogarithmic coordinates as a function of the reciprocal of the LHSV. The slope of the resulting straight line is utilized to determine the RA of the tested catalyst. The ratio of the slope of the tested catalyst to that of a standard catalyst, or another tested catalyst, (assigned an RA of 100) when multiplied by 100, is the relative activity of the tested catalyst.

In the present illustration, catalyst A, the more porous of the two composites, was assigned a relative activity of 100 with respect to both asphaltene conversion and hydrocracking activity. A comparison of catalysts A and B is presented in the following Table III:

The analytical data are those from the test period at 0.5 LHSV.

The /s-inch reactor tube was then loaded with 80.0 cc. of catalyst A, in eight 10 cc. alternating beds with 2.0 cc. of sand, above 70.0 cc. of catalyst B, in seven 10 cc. altemating layers with 2.0 cc. of sand. Thus, while the quantity of each catalyst was approximately halved, the total amount of catalyst remained at 150 cc. A relative activity test, as above described, was performed, the results of which are presented in the following Table IV:

TABLE IV Relative Activity, Piggyback Catalyst System Hcplanc inwlublcs, wt. 5 0. l 8 Sulfur, wt. l: 0.ll Vol. distilled at 1050 F. 90.4

RA, heptane insolubles RA, hydrocracking From the above data, again those from the test period at 0.5 LHSV, it will be readily ascertained that the desirable attributes of both catalysts have been advantageously employed. Considering that only half of each catalyst was employed 80.0 cc. ofA and 70.0 cc. ofB, versus cc. of eachthese results are surprising and unexpected.

The foregoing illustrates the present invention and the benefits afforded through the utilization thereof.

I claim as my invention:

1. A process for the conversion of an asphaltene-containing hydrocarbonaceous char e stock which comprises reacting said charge stock and by ogen in a first reaction zone, in contact with a first catalytic composite, more than 50.0 percent of the macropore volume of which is characterized by pores having pore diameters greater than about 1,000 angstroms, and reacting the resulting first zone effluent and hydrogen in a second reaction zone, in contact with a second catalytic composite, less than 50.0 percent of the macropore volume of which is characterized by pores having pore diameters greater than 1,000 angstroms.

2. The process of claim 1 further characterized in that said first and second catalytic composites contain at least one metallic component from Groups VI-B and Vlll combined with a porous carrier material.

3. The process of claim 1 further characterized in that said first catalytic composite comprises a porous carrier material containing from about 5.0 percent to about 30.0 percent by weight of boron phosphate.

4. The process of claim 1 further characterized in that said second catalytic composite comprises a porous carrier material containing less than about 5.0 percent by weight of boron phosphate.

5. The process of claim 1 further characterized in that said first catalytic composite is oxidized at a temperature above about 600 C.

6. The process of claim 1 further characterized in that said second catalytic composite is oxidized at a temperature below about 600 C.

7. The process of claim 2 further characterized in that said first and second catalytic composites contain from about 4.0 percent to about 30.0 percent by weight of said Group Vl-B metal component and from about i.0 percent to about 10.0 percent by weight of said Group VIII metal component. 

2. The process of claim 1 further characterized in that said first and second catalytic composites contain at least one metallic component from Groups VI-B and VIII combined with a porous carrier material.
 3. The process of claim 1 further characterized in that said first catalytic composite comprises a porous carrier material containing from about 5.0 percent to about 30.0 percent by weight of boron phosphate.
 4. The process of claim 1 further characterized in that said second catalytic composite comprises a porous carrier material containing less than about 5.0 percent by weight of boron phosphate.
 5. The process of claim 1 further characterized in that said first catalytic composite is oxidized at a temperature above about 600* C.
 6. The process of claim 1 further characterized in that said second catalytic composite is oxidized at a temperature below about 600* C.
 7. The process of claim 2 further characterized in that said first and second catalytic composites contain from about 4.0 percent to about 30.0 percent by weight of said Group VI-B metal component and from about 1.0 percent to about 10.0 percent by weight of said Group VIII metal component. 